Measurements of siderophore production in the rhizosphere

Siderophore producing bacteria are commonly isolated from the plant rhizosphere and can be shown to produce iron chelating substances by growth on indicator media such as chrome azurol S (Koedam et al., 1994 Milagres et al., 1999 Calvente et al., 2001). In general, there do not appear to be any differences in the population densities of culturable, siderophore producing bacteria in the rhizosphere of different plant species (Alexander and Zuberer, 1991). The wide ability of microorganisms to...

Erwinia chrysanthemi A Pathogen Of Agricultural Importance

Pectinolytic Erwinia, recently reclassified in the genus Pectobacterium, forms one of the two groups within enterobacteria that contain species pathogenic to plants. A typical member in this group is E. chrysanthemi, a pathogen that can prosper in various environments and cause disease in economically important plants, including vegetables (potato, chicory, maize, etc.) and ornamentals (African violet, carnation, orchids, etc.). Soft rot, the most visible symptom induced by this species,...

Competition between siderophores

The primary function of siderophores is to increase the fitness of bacteria in iron-limiting soils so that they can acquire sufficient amounts of this element for growth. Bacteria have many different functions in soils in which they degrade plant detritus, fix nitrogen, detoxify potentially toxic chemicals, and interact with plants to promote plant growth or to cause plant diseases. Under highly competitive conditions, the ability to acquire iron via siderophores may determine the outcome of...

Iron requirements in animals

Iron has been recognized as a required nutrient for animals for more than 100 years (Pond et al., 1995). Still, sub-clinical iron deficiencies occur more frequently than recognized by most livestock producers. Currently, micronutrient deficiency is a bigger problem than macronutrient deficiency, because the farmer does not readily see specific symptoms that are characteristic of a trace mineral deficiency. Instead, the animal grows or reproduces at a reduced rate, uses feed less efficiently and...

Iron Nutrition In Field Crops

HOPKINS2, JASON W. ELLSWORTH3 and VON D. JOLLEY4 1Department of Soil and Crop Sciences, 1170 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523-1170, USA. 2Cropping Systems, 1776 Science Center Dr., University of Idaho, Idaho Falls, ID, USA. Twin Falls R & E Center, University of Idaho, 315 Falls Avenue, Evergreen Building, P.O. Box 1827, Twin Falls, Idaho 83303-1827, USA. 4Department of Plant and Animal Sciences, Brigham Young University, 253...

Management of irrigation and drainage fertility and seeding practices

Cultural practices often impact the severity of Fe chlorosis and manipulation of these practices can be effective remedies. Interacting management issues include poor drainage, compaction, salinity, fertility, irrigation, seed, and herbicides. Iron chlorosis is frequently observed in poorly drained portions of a field (Bloom and Inskeep, 1986 Franzen and Richardson, 2000 Hansen et al., 2003 Inskeep and Bloom, 1986, 1987 Moraghan and Mascagni, 1991). The chemical and biological reactions that...

Ferritin Overexpression In Transgenic Plants And Its Consequences

Iron accumulation in various plant tissues is under genetic control and this is evidenced by alteration of Fe homeostasis either in plant mutants altered in Fe signalling or in transgenic plants overexpressing ferritin ectopically. Our knowledge of the role that ferritins play in plant physiology is still very limited. Their functions have been recently addressed by an approach based on their over-expression in transgenic plants, either in the plastids (their natural cytological localization)...

Management Of Iron Nutrition In Field Crops

Management of Fe nutrition is unique compared to most essential nutrients for which deficiencies are easily corrected by adding relatively inexpensive fertilizer. Although soil chemistry and environmental conditions result in various inefficiencies with these other nutrients, these deficiencies are generally corrected with adequate fertilizer addition (Tisdale et al., 1993). Alternatively, Fe deficiencies are not easily corrected with fertilizers applied to the soil in typical fashion...

Content of phytosiderophores amino acids organic acids and metals

The form in which Fe is translocated in Strategy II plants is still a problem that needs to be solved. In dicot plants, citrate is a predominant carrier of Fe in xylem tubes (Brown and Chaney, 1971 Brown and Tiffin, 1965 Lopez-Millan et al., 2000 2001 Tiffin, 1966). Ion concentrations of xylem exudate from stem incisions have been measured (Hocking, 1980 White et al., 1981). Many researchers have discussed the mechanisms of translocation of micronutrients in monocot or dicot plants (Kochian,...

Other mineral and organic iron sources

Ferrous sulfate, applied to the soil or to the tree (leaf treatments, trunk injection), has been the major therapy against Fe chlorosis from the first description of this nutritional disorder until the introduction of Fe synthetic chelates, and is still widely used by fruit growers in some developing countries, due to its low cost. If supplied alone, Fe(II)sulfate is of little or no agronomic value in calcareous soils, where the Fe2+ is subject to rapid oxidation. For example, Fe sulfate was...

Variety selection and screening for tolerance

In general there are two methods of screening cultivars for resistance to Fe deficiency chlorosis. The standard is field screening, including greenhouse and environmental chamber evaluations, where chlorosis is rated among the varieties compared to a control. The second method is to quantify one or more specific physiological responses to induced Fe deficiency stress Field screening has been and continues to be the primary technique for isolating soybean genotypes with resistance to Fe...

Heavy metal availability in the soil

Chemical analysis of the soil reveals the concentration of metals but provides little information on their phytoavailability. Even mobile metals are present in the soil in several forms of different mobility, including hydrated ions, soluble organic and inorganic complexes and constituents of floating colloid particles in the soil solution, as exchangeable ions adsorbed on colloid surfaces and in the silicate crystals of the solid phase. There is a dynamic exchange between all these different...

Conclusion And Future Outlook

In this chapter Fe-chelates have been presented as the most efficient, but expensive, fertilizers to correct Fe chlorosis. Their chemical equilibria, the sorption into soil surfaces, the plant acquisition of Fe from chelates and the remobilization of Fe from native forms present in soils seems to play important roles in their mechanism of action, but the quality and effectiveness of commercial products can still be considerably improved. In the future, research should focus on the synthesis and...

Dissolution Of Soil Native Iron By Chelating Agents

When the Fe-chelate releases Fe to the plant, the chelating agent may dissolve native Fe (Figure 5-1), which can be then transported to the plant (Chen and Barak, 1982 Lindsay, 1995 Lucena, 2003). However, the importance of this dissolution process in plant Fe nutrition is not well known. Schwertmann (1991) reviewed the knowledge on the processes of dissolution of Fe oxides, indicating that most of the studies concerning chelating agents have been done for the estimation of the plant-available...

Inoculation of plants with siderophore producing microorganisms

The ability of plants to utilize microbial siderophores as iron sources for growth is highly controversial and has been investigated using a variety of experimental approaches using hydroponic and soil culture. Although there are considerable differences in the quantities of siderophores that are produced by various strains and species of bacteria, there is no evidence to date that inoculation with bacterial strains that produce high quantities of siderophores is beneficial to plant iron...

Of xylem sap of barley and rice grown hydroponically under varied concentrations of iron

As shown in the previous section 4.1, the concentration of PS was much higher than that of Fe in xylem sap of -Fe barley. The ratio of the concentration of PS Fe varied depending on Fe nutritional status of the plant. In order to obtain data for the PS Fe ratio as affected by the Fe status of the plant, the xylem sap from grasses grown with various concentrations of Fe (0, 1, 10, 100 M) in hydroponic culture was collected and analyzed. Iron sources in the hydroponics media for barley and rice...

Utilization of microbial siderophores by plants

Numerous studies have investigated the ability of plants to use microbial siderophores as iron sources for growth (Table 8-2), and have examined the possible mechanisms by which plants might obtain iron from these compounds, either by exchange with phytosiderophores or by the iron reductase that is expressed by Strategy I plants. However, these experiments have been controversial for several reasons. Since siderophores are labile and are subject to degradation after their addition to soil,...

Occurrence Of Iron Deficiency In Field Crops

Iron deficiencies have been reported for many plant species and geographical regions. The most common problems correspond to the cultivation of sensitive crop species Table 2-1 in arid and semi-arid regions with calcareous soils presence of free carbonates . Iron deficiency is widely reported in soybean Glycine max L. Merr. , peanut Arachis hypogaea L. , dry bean Phaseolus vulgaris L. , sorghum Sorghum bicolor L. Moench , and rice Oryza sativa L. . Additional Fe deficiency is reported under...

Stability And Speciation Of Iron Chelates In Soil Solution

Four processes may be involved in the reaction of Fe-chelates with soil that may reduce their presence in the soil solution Fe-chelate or chelating agent degradation Replacement of the Fe by competing metals FeY- M2 3H2O S Fe OH 3 MY2- 3H Sorption of the Fe-chelate onto the soil surfaces Chemical degradation of Fe-chelates is slow in the dark Hill-Cottingham, 1955 Lahav and Hochberg, 1975 . Thus, they have been considered as non-environmentally degradable, despite the fact that no experimental...

Soil Properties Associated With Iron Deficiency

Iron comprises approximately 5 of the earth's crust and is the fourth most abundant element in the lithosphere Tisdale et al., 1993 , and as a result, plants are growing in a sea of Fe. However, the bioavailability of Fe in alkaline soil is very low Chen and Barak, 1982 Jolley and Brown, 1994 Lindsay and Schwab, 1982 Vose, 1982 . It is well documented that Fe deficiency in field crops primarily occurs in high pH, alkaline soils calcareous conditions Hansen et al., 2003 Inskeep and Bloom, 1984 ....

Fertilizer and cultural management practices

Although the use of Fe-efficient plants is generally the best approach to preventing Fe availability problems Goos and Johnson, 2000 Hansen et al., 2003 Jolley and Brown, 1994 , several fertilizer and cultural management strategies are also available for use alone or in combination, to prevent correct Fe deficiency, including 1 lowering soil pH, 2 applying foliar Fe fertilizer or acid sprays, 3 applying chelated complexed Fe fertilizers to the soil, 4 applying Fe fertilizer materials in a...

Zea mays Maize Strategy II

Zea mays L. is an extremely phenotypically variable grass species which in conjunction with seven other genera are included in the family Maydeae Russel and Hallauer, 1980 . Three genera are native to the Americas, Zea, Euchlaena, and Tripsacum, and five others are native to southeastern Asia and Australia. The maize plant is monoecious, with male flowers in the tassel and female flowers on the ear shoot, and the species is primarily cross-pollinated. Intergeneric crosses of Zea have been...

Interaction in the rhizosphere

Organic ligands bind metal ions with different stability constants. In the soil solution in the rhizosphere, metals can either form this kind of complexes or precipitate with inorganic anions. Knowing the stability constants of complexes Table 6-1 and the pH of the nutrient solution, it is possible to theoretically predict which metals and ligands will form complexes and which will precipitate, using specialized software developed for this purpose MinteqA2, Allison et al., 1991 Geochem-PC,...

Siderophore Producing Rhizobium Japonicum

H. 1999 Growth and siderophore production in Bradyrhizobium lupin strains under iron limitation, Folia Microbiol. 44, 196-200. Andrews, S. C. 1998 Iron storage in bacteria, Adv. Microbial. Physiol. 40, 281-351. Appleby, C. A. 1984 Leghemoglobin and Rhizobium respiration, Annu. Rev. Plant Physiol. 35, 443-478. Arahou, M., Diem, H. G. and Sasson, A. 1998 Influence of iron depletion on growth and production of catechol siderophores by different Frankia strains, World J. Microbiol....

The Zip Family

The ZIP family was named after its founding members, Zrt1p and Zrt2p in yeast and IRT1 in A. thaliana Eide et al., 1996 Zhao and Eide, 1996a, 1996b . As we will discuss below, IRT1 is the major iron transporter responsible for iron uptake from the soil and Zrt1p and Zrt2p are zinc transporters. There are now more than 100 members of this family found in many diverse organisms including bacteria Grass et al., 2002 , Drosophila Mathews et al., 2005 , mammals Dufner-Beattie et al., 2003 Eide, 2003...

The Metabolism Of Iron By Nitrogenfixing Rhizospheric Bacteria

JOHNSON and YVONNE M. BISHOP Department of Biology, University of New Mexico, MSC03 2020, Albuquerque, New Mexico 87131-0001, USA. E-mail lbarton unm.edu Abstract Nitrogen-fixing bacteria require iron for rhizospheric growth as well as for plant-associated symbiotic activities. One of the iron uptake systems involves siderophores and bacteria produce a great diversity of ferric ion chelators in iron-limited environments. This review examines some of the free-living...

Chlorophyll mg g1 fw 208 017 074 025 021 021

Recovery of Fe-deficiency symptoms in cucumber plants after addition of different Fe sources 0.2 M Fe to a nutrient solution buffered at pH 7.5 modified from Pinton et al, 1999a . 59Fe-WEHS could also be used by barley plants Strategy II via a mechanism which may involve ligand exchange between phytosiderophores and WEHS Cesco et al, 2002 . In fact, a high rate of 59Fe-WEHS uptake in Fe-deficient plants could be observed during the period of high phytosiderophore release. The very...

Auxin Ethylene And Their Interactions

Auxin is a plant hormone involved in many plant growth metabolic processes, such as the regulation of growth, apical dominance, emergence of lateral roots, root hair differentiation, vascular differentiation, leaf epinasty, and others Bhalerao et al., 2002 Ljung et al., 2001 Rahman et al., 2002 . The major endogenous auxin in plants is IAA indole-3-acetic acid , although there are also other natural auxins, such as IBA indole-3-butyric acid Bhalerao et al., 2002 . In addition, there are also...

References

Abrams, S. 2004 New approaches to iron fortification the role of bioavailability studies, Am. J. Clin. Nutr. 80, 1104-1105. Afsana, K., Shiga, K., Ishizuka, S. and Hara, H. 2003 Ingestion of an indigestible saccharide, difructose anhydride III, partially prevents the tannic acid-induced suppression of iron absorption in rats, J. Nutr. 133, 3553-3560. Afsana, K., Shiga, K., Ishizuka, S. and Hara, H. 2004 Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper...

Quality Of Commercial Iron Chelates

Commercial products are obtained by carrying out first the industrial synthesis of the chelating agents and then incorporating Fe from inorganic salts. While the first synthesis pathways proposed produced quite pure compounds Kroll et al., 1957 , the industrial synthesis pathways used nowadays Dexter, 1958 Petree et al., 1978 yield commercial products with quite different purities, and also lead to the presence of by-products. For instance, the condensation product 2,6-di CH COOH NHCH2 CH2NHCH...

Functional classification of cytoplasmic polypeptides

The polypeptides that were identified can be subdivided into groups with respect to their predicted functions Table 19-1 . The first category contains polypeptides presumably involved in regulation of translation. Eukaryotic translation and or initiation factors are essential components for protein synthesis and polypeptide elongation. The translation initiation factor elF-4A, the elongation factor elF-2 and elongation factor tufA were all consistently decreased under Fe deficiency. In...